<Article updated with more accurate calculation>
There are some impressive new scores at storageperformance.org, with the usual crazy configurations of thousands of drives etc.
When looking at $/IOP, make sure you are comparing list price (look at the full disclosure report, that has all the details for each config).
Otherwise, you could get the wrong $/IOP since some vendors have list prices, others show heavy discounting.
For example, a box that does $6.5/IOP after 50% discounting, would be $13/IOP using list prices.
As I have mentioned in other posts, RAID plays a big role in both protection and performance.
Most SPC-1 results are using RAID10, with the notable exception of NetApp (we use RAID-DP, mathematically analogous to RAID6 in protection).
Here’s a (very) rough way to convert a RAID10 result to RAID6, if the vendor you’re looking for doesn’t have a RAID6 result, but you know the approximate percentage of random writes:
- SPC-1 is about 60% writes.
- Take any RAID10 result, let’s say 200,000 IOPS.
- 60% of that is 120,000, that’s the write ops. 40% is the reads, or 80,000 read ops.
- If using RAID6, you’d be looking at roughly a 3x slowdown for the writes: 120,000/3 = 40,000
- Add that to the 40% of the reads and you get the final result:
- 80,000 reads + 40,000 writes = 120,000 RAID6-corrected SPC-1 IOPS. Which is not quite as big as the RAID10 result…
- RAID5 would be the writes divided by 2.
Just make sure you’re comparing apples to apples, that’s all. I know we all suffer from ADD in this age of information overload, but do spend some time going through the full disclosure, since there’s always interesting stuff in there…